This open access book Design Participation presents doable and demonstrated ways by which design can become a major contributor to social and environmental change. This entails a shift from seeking to define solutions to opening spaces in which others—activists, entrepreneurs, civil servants, neighborhood communities, politicians (and so on) —can effectively elaborate on and find (re)solutions to the matters they are facing. It is now time to pursue design participation for real: in earnest, skillfully and for real problems. Building on a twenty-year research program, Design Participation shows that participation matters and provides an encompassing resource for understanding the matters of participation: how to think, reflect, plan and work in design participation in different settings and for different issues.